""4. Support chips: STC89C52 STC12C5A60S2 STC11/10 x series of AT89S52 and compatible with the chip pins of the chip""
Those are single-chip microcontrollers. The 89C52 probably was derived from older Intel products. Data for all of the listed parts are all over the innergoogle.
I have not read any of the datasheets, so this is a guess:
The 11 MHz clock suggests that the chip has an internal RS-232 format serial port (without the drivers and receivers), but there is nothing on the board for on-board programming. You write and debug the code on a development system, then use a device programmer to transfer the compiled code to the chip, then plug the chip into this board.
ak